Fix redefinition of state machine

core/app/models/spree/order/checkout.rb

@@ -36,7 +36,7 @@ def self.define_state_machine!
  # To avoid multiple occurrences of the same transition being defined
  # On first definition, state_machines will not be defined
  state_machines.clear if respond_to?(:state_machines)
- state_machine :state, initial: :cart, use_transactions: false, action: :save_state do
+ state_machine :state, initial: :cart, use_transactions: false do
  klass.next_event_transitions.each { |t| transition(t.merge(on: :next)) }
 
  # Persist the state on the order